High capacitance multilayer with high voltage capability

ABSTRACT

New designs for multilayer ceramic capacitors are described with high voltage capability without the need of coating the part to resist surface arc-over. One design combines a high overlap area for higher capacitance whilst retaining a high voltage capability. A variation of this design has increased voltage capability over this design as well as another described in the prior art although overlap area and subsequently capacitance is lowered in this case. These designs are compared to the prior art in examples below.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to pending U.S. ProvisionalApplication No. 61/222,296 filed Jul. 1, 2009.

BACKGROUND OF INVENTION

The present invention is related to a capacitor exhibiting highcapacitance per unit volume. More specifically, the present invention isrelated to an improved conductive inner electrode design which improveselectrode overlap, and therefore capacitance, with high voltage ratingand no arc-over.

Traditional high voltage capacitor designs, such as for use at ≧500Vdc,typically combine 2 or more capacitors in series within the samemultilayer ceramic device package. These serial designs are effective atincreasing effective voltage since the effective voltage is dividedbetween the 2 capacitors. Capacitors arranged in series are alsoeffective in decreasing the occurrence of surface-arc-over.Unfortunately, the effective capacitance, C_(eff), of a serial device issignificantly lowered since 1/C_(eff)=Σ1/C_(n) where n is the number ofcapacitors in series.

The practitioner has therefore had to balance the desire for highvoltage capability, which can be improved by serial capacitors, with thedesire for high capacitance, which is compromised with serialcapacitors.

For voltages up to about 2,500 Vdc the capacitance can be increased withminimal flash over by coating the capacitors themselves, or the board orassembled device, using standard MLCC designs. In the case of theindividual monolithic multilayer capacitors the leads are attached andthe part epoxy coated. A significant disadvantage to this approach isthat the leaded part cannot typically be used in an automated surfacemount assembly process and there is some additional cost associated withthe leads and epoxy.

One approach to mitigate the problem associated with flashover isdescribed in U.S. Pat. No. 6,134,098 wherein lower K dielectric layersare used on the top and bottom of a series capacitor design. Althoughthis approach is effective to decrease flash over this is still a serialcapacitor design and the effective capacitance is lower as detailedabove. Furthermore, differences in the thermal expansion coefficient ofthe various materials are problematic since thermal stresses are createdduring firing.

Japanese Patent Abstract 2006-066831 by SHIMIZU MICHINAO, ITO KAZUNORIand KOMATSU TOSHIAKI discloses a multilayer ceramic capacitor designwhich raises the starting voltage of the surface discharge. To achievethis effect a serial type arrangement of capacitors, using multipleinternal electrode prints, is required.

Coating of parts whilst retaining the ability to surface mount canretard arc over. U.S. Pat. No. 6,627,529, by Duva and related U.S. Pat.No. 6,683,782, both of which are incorporated herein by reference,describe the benefits, and method, for applying para-xylylene polymercoatings to multi-layer ceramic capacitors. Coating individual parts, orthe final assemblies, is cost prohibitive so these approaches have beenrestricted to high value added applications in electronics.

Capacitance, C, is defined by the following equation; C=∈_(r)∈₀An/t;where ∈_(r) is the relative permittivity of the dielectric; ∈₀ is aconstant equal to the permittivity of free space; A is the overlap areafor each internal conductive layer, also referred to as an active; n isthe number of actives and t is the separation distance or thicknessbetween the electrodes. Therefore, it is an ongoing desire to increasethe number of layers and overlap area while decreasing the layerseparation. Often the efforts to increase voltage are contrary to one,or more of these desires.

For example, in a more recent approach presented in U.S. Pat. No.7,336,475 by Bultitude et al, which is incorporated herein by reference,shield electrodes are used which allow for a high voltage capability byprohibiting surface-arc-over whilst retaining a relatively high overlaparea for high capacitance in a non-serial design. This design combines atop and bottom shield electrode that protects the oppositely chargedelectrode below from arc-over from the terminal in contact with theshield. Side shields are also described which function in a similarmanner by protecting each active electrode along the side of the part byconnecting to the terminal of opposite polarity while overlapping theactive electrode to prevent arc over.

US Pat. Publ. No. 2009/0052111 also to Bultitude, the entirety of whichis incorporated by reference, describes the use of a coating ofpolyimide applied by spin coating to further increase voltage breakdown.Related US Pat. Publ. No. 2009/0052112, the entirety of which isincorporated by reference, describes the need to shield between theterminal and the opposed electrode. In both cases the MLCC designsdescribed use side shields connected to the opposed terminal.

The presence of side shields connected to the opposite terminal in eachof the active layers confers a risk of a breakdown pathway between theshields and the active electrode. This pathway may occur due tocontamination or electrode “bleed out” during the electrode printingprocess that would result in a short circuit and catastrophic failure ofthe capacitor. Furthermore, although the prior art designs have moreoverlap, and therefore higher capacitance, than the serial designs theside shields take-up a significant area which does not contribute tocapacitance. The area occupied by the side shields decreases theavailable capacitance as a function of total volume since the areaoccupied by the shields can not be utilized for electrode overlap.

In spite of the advances in the art there is still a long standingdesire for a capacitor with improved capacitance, for use in highvoltage applications, which has minimal flashover. Such a capacitor isprovided herein.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a capacitor with reducedflashover, also called surface-arc-over, without the need for anothertype of dielectric with potential thermal mismatch issues betweendifferent dielectrics whilst maintaining a high capacitance.

It is another object of the invention to provide a capacitor withimproved capacitance, per unit volume, without loss of effective voltagerating and with decreased flashover.

These and other inventions, as will be realized an improved capacitor.The capacitor has first internal conductors and second internalconductors in an alternating layer wherein the first internal conductorhas a first polarity and the second internal conductor has opposingpolarity. A first external termination is in electrical contact with thefirst internal conductors wherein the first external termination has afirst side extension which extends a distance along a side of thecapacitor which is perpendicular to the first internal conductors andthe second internal conductors. A second external termination is inelectrical contact with the second internal conductors wherein thesecond external termination has a second side extension which extends asecond distance along a second side of the capacitor which isperpendicular to the first internal conductors and the second internalconductors. The first internal conductors extend towards the secondexternal termination to a separation distance from the second externaltermination which is less than the second distance. The first internalconductors comprise a bulk region and a secondary region wherein thesecondary region has a region width which is less than a bulk width ofthe bulk region.

Yet another embodiment is provided in an improved capacitor. Thecapacitor has first internal conductors and second internal conductorsin an alternating layer wherein the first internal conductor has a firstpolarity and the second internal conductor has opposing polarity. Afirst external termination is in electrical contact with the firstinternal conductors wherein the first external termination has a firstside extension which extends a distance along a side of the capacitorwhich is perpendicular to the first internal conductors and the secondinternal conductors. A second external termination is in electricalcontact with the second internal conductors wherein the second externaltermination has a second side extension which extends a second distancealong a second side of the capacitor which is perpendicular to the firstinternal conductors and the second internal conductors. The firstinternal conductors extend towards the second external termination to aseparation distance from the second external termination which is lessthan the second distance. The first internal conductors comprise a bulkregion and a secondary region wherein the secondary region is furtherfrom the second side extension than the second distance.

Yet another embodiment is provided in a method of forming anmultilayered ceramic capacitor. The method includes the steps of:

printing a pattern of print regions of conductive material on a seriesof sheets wherein each print region has a bulk region and a secondaryregion wherein the secondary region has a region width which is lessthan a bulk width of the bulk region;forming a layered assembly by the steps of:overlaying a first sheet over a bottom sheet in parallel offset fashionwherein at least one print region of the bottom sheet is overlapped butlaterally offset from a print region of the first sheet with adielectric precursor between the overlapped but laterally offset printregions;overlaying a second sheet over the first sheet wherein at least oneprint region of the second sheet is overlapped but offset from the printregion of the first sheet and the print region of the bottom sheet witha dielectric between the overlapped but laterally offset print regions;overlaying additional sheets with alternating sheets having the printregion aligned with the first sheet and the second sheet respectivelywith a dielectric between the overlapped but laterally offset printregions,overlaying a top sheet with the print region aligned with the bottomsheet with a dielectric between the overlapped but laterally offsetprint regions;compacting and dicing the overlayed sheets to isolate a layeredstructure with print regions of the first layer forming first internalconductors; print regions of the second layer forming second internalconductors and print regions of the top sheet and the bottom sheetforming shield layers;firing the compacted and diced overlayed sheets to remove organicmaterials and fuse the overlayed sheets into a fired monolith;forming a first external termination in electrical contact with thefirst internal conductors; andforming a second external termination in electrical contact with thesecond internal conductors.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 is a schematic cross-sectional view of a capacitor.

FIG. 2 is a schematic cross-sectional view of a capacitor taken alongline 2-2 of FIG. 1.

FIG. 3 is a schematic cross-sectional view of a capacitor.

FIGS. 4A-4F are schematic representations of conductive innerelectrodes.

FIG. 5 is a schematic representation of an active electrode print.

FIG. 6. is a schematic representation of an top and bottom shieldelectrode print.

FIG. 7 is a schematic representation of an active electrode print.

FIG. 8 is a schematic representation of an active electrode print.

FIG. 9 is a schematic representation of an active electrode print.

FIG. 10A-F are schematic representations of conductive inner electrodes.

FIG. 11 is a schematic representation of an active electrode print.

FIG. 12 is a schematic cross-sectional view of a capacitor.

FIG. 13 is a schematic cross-sectional view of the capacitor of FIG. 11taken along line 13-13.

FIG. 14 is a schematic cross-sectional view of the capacitor of FIG. 11taken along line 14-14.

FIG. 15 is a schematic representation of an active electrode print.

DETAILED DESCRIPTION

The present invention is directed to an improved capacitor. Morespecifically, the present invention is directed to a capacitor withimproved geometry of inner conductive layers.

The invention will be described with reference to the various figureswhich are an integral non-limiting component of the disclosure.Throughout the figures similar elements will be numbered accordingly.For simplicity, a minimal number of active layers is illustrated withthe understanding that the actual number used may be quite large.

A cross-sectional schematic view of a multi-layer ceramic capacitor ofthe present invention is illustrated schematically in FIG. 1. In FIG. 1,the capacitor, generally represented at 10, comprises a multiplicity ofconductive inner electrodes, 11 and 12, of alternating polarity withdielectric ceramic layers, 15, dispersed there between. The alternatingconductive inner electrodes terminate at opposing external terminals, 13and 14. An insulating layer, 16, may be applied.

A cross-sectional schematic view of the capacitor of FIG. 1 taken alongline 2-2 is provided in FIG. 2. In FIG. 2, an arc point exist as theclosest point between the side extension, 17, of the externaltermination, 14, and the closest extent, 18, of the conductive innerelectrode, 11, of opposing polarity.

An embodiment of the invention is illustrated in cross-sectionalschematic view taken parallel to the inner electrodes in FIG. 3. In FIG.3, a first conductive inner electrode, 111, is in electrical contactwith an external termination of common polarity, 113. A secondconductive electrode, 112, is also in electrical contact with anexternal termination of common polarity, 114, with the first and secondconductive inner electrodes being of opposing polarity as would berealized. Dielectric, 115, is between and around the conductiveelectrodes. An insulating layer, 116, may be applied.

For the purposes of discussion the first conductive inner electrode andsecond conductive inner electrode are of the same shape and size.Different shapes and sizes are functional yet for manufacturing purposesit is highly desirable that they be the same since each is designed tobe as large as possible within the constraints of avoiding flashover aswill be more fully described. In the discussion, conductive innerelectrode will refer to one layer or both layers.

The inner conductive layer is defined as having a bulk zone, 120, whichis most preferably rectangular, and a secondary zone, 121. The bulk zoneand secondary zone are defined for the purposes of geometry and takentogether they form a seamless inner conductive layer preferably with nodifference in layer thickness or composition. At least a portion of thesecondary zone is a distance, D¹, which is closer to the externaltermination of opposing polarity than the distance, D², which is thedistance the external termination side extension, 117, extends along theside away from the external termination.

The bulk zone, 120, preferably is as large as possible to provide themost overlap with the inner conductive layer of opposing polarity. Thesecondary zone, 121, comprises a region which has a width which isnarrower than the width, W, of the bulk zone. The narrowed region of thesecondary zone insures that the closest distance between the externaltermination side extension, 117, and the narrowed portion, 118, of thesecondary zone is at least as large as the closest separation distancebetween the conductive inner electrode and external termination ofopposing polarity, represented as D1. The height of the bulk zone, H, ispreferably at least 66% of the longest length of the inner conductivelayer measured from the contact point with the exterior termination ofcommon polarity. A height of the bulk zone of as low as 25% has beendemonstrated successfully.

Representative conductive inner electrodes are illustrated schematicallyin FIGS. 4A-4F wherein each conductive inner electrode, 111, isillustrated with a rectangular bulk zone, 120, and a secondary zone,121.

In FIG. 4A, the secondary zone comprises a semiround shape. Thesemiround shape can have the same radius over the entire zone therebyforming a semicircle. Alternatively, the radius can vary thereby forminga semi-oval shape or a semi-obround shape wherein an obround shapeconsist of two semicircles connected by parallel lines tangent to theirendpoints.

In FIG. 4B the secondary zone comprises a partially rounded rectangularshape. The rounded portions may have the same radius over the entireround zone thereby forming a semicircle or the radius can vary therebyforming a semi-oval shape or a semi-obround shape.

In FIG. 4C the secondary zone is trapezoidal with the shorter parallelface preferably opposite to the bulk zone.

In FIG. 4D the secondary zone is rectangular with a length, L, which isless than the width, W, of the bulk zone.

In FIG. 4E the secondary zone is a concave trapezoid wherein thenon-parallel sides of a trapezoid are concave. The concave shape ispreferably rounded and may have the same radius over the entire roundzone thereby forming a semicircle or the radius can vary thereby forminga semi-oval shape or a semi-obround shape as described relative to FIG.4A.

In FIG. 4F the secondary zone is a combination with a first secondaryzone being trapezoidal and the second secondary zone being semiround.

In the secondary zone the radius of any rounded portion is sufficientlylarge that the separation between the closest extent of the externaltermination side extension and the inner conductive electrode is largerthan the separation between the secondary portion and the externaltermination of opposing polarity.

The dielectric ceramic layers preferably comprise a dielectric ceramiccomposition. The major constituent material for the ceramic, forexample, may be made of BaTiO₃, BaCaTiZrO₃, BaCaZrO₃, BaZrO₃, CaZrO₃and/or CaTiO₃ but the current invention is not particularly limiting tothe type of ceramic dielectric material used and other dielectricmaterials, insulators, magnetic materials and semiconductor materials,or combinations thereof, as known in the art. The dielectric ceramiccomposition can be used in conjunction with precious metal or base metalinner electrodes. Cheaper base metal electrodes are most preferred andthey require a non-reducible ceramic which can be sintered in a reducingatmosphere below the melting temperature of common base metals, such asnickel, without detriment to the electrode thereby yielding a capacitorwith high electrode continuity and excellent electrical properties.

The conductive inner electrodes comprise precious metal or base metal.Common base metals include nickel, tungsten, molybdenum, aluminum,chromium, copper or an alloy thereof which can be fired in a reducingatmosphere. Common precious metals are silver, palladium, platinum, goldor alloys thereof. Most preferably the base metal is nickel.

The composition of the external terminations and side extensions is notparticularly limiting herein and any composition typically employed inthe art is sufficient. Silver, palladium, copper, nickel or alloys ofthese metals compatible with the inner electrodes blended with variousglass frits are particularly relevant. A plating layer or multipleplating layers can be formed on the external end terminations.

Because of the use of base metals in the conductive inner electrodes,the capacitor of the present invention is preferably fired in a reducingatmosphere. The reducing overall atmosphere average PO₂ is preferablybetween 10⁻³ to 10⁻¹⁸ atm, while the PO₂ in localized regions within thecapacitor monolith have been estimated to be as low as ˜10⁻²⁸ atm (C. A.Randall, et al., “A Structure-Property-Processing Approach Targeted tothe Challenges in Capacitive Ceramic Devices,” CARTS USA 2006PROCEEDINGS, at 3-12, Apr. 3-6, 2006).

An advantage of the present invention is the ability to use the samematerials commonly employed and the conventional tape casting processfamiliar to those skilled in the art. In this process the ceramicpowder, such as the preferred base metal compatible X7R dielectriccomprising a substantial portion of barium titanate, is dispersed in anorganic medium then cast into a tape.

Some of the tape is printed with the electrode pattern, in this case apaste of nickel in organic medium.

Merely as an example of the manufacturing process of the presentinvention, a ceramic slurry is prepared by blending and milling theceramic compounds of choice with a dispersant in either water or anorganic solvent such as, for example, ethanol, isopropanol, toluene,ethyl acetate, propyl acetate, butyl acetate or a blend thereof. Aftermilling a ceramic slip is prepared for tape-casting by adding a binderand a plasticizer to control rheology.

The slip is then processed into a thin sheet by tape-casting. Afterdrying the sheet, a multiplicity of electrodes are patterned on thesheet by using, for example, a screen-printing method to form a printedceramic sheet.

A laminate green body is prepared by stacking onto a substance such aspolycarbonate, polyester or a similar method: 1) a certain number ofunprinted ceramic sheets representing the bottom covers, then 2) acertain number of printed ceramic sheets in alternate directions so asto create alternating electrodes that terminate at opposing ends, and 3)a certain number of unprinted ceramic sheets representing the topcovers. Variations in the stacking order of the printed and unprintedsheets can be used with the dielectric material of this invention. Thestack is then pressed at between 20° C. and 120° C. to promote adhesionof all laminated layers. The laminated green body is then cut intoindividual green chips.

Capacitors made with precious metal inner electrodes can be sintered inair up to temperatures not exceeding 1400° C. In the case of base metalsthe ceramic is then sintered in a reductive atmosphere with a partialoxygen partial pressure of 10⁻³ to 10⁻¹⁸ atm at a temperature not toexceed approximately 1500° C.

The sintered capacitor is preferably subjected to end surface grindingby barrel or sand blast, as known in the art, followed by applyingexternal electrode paste to form the terminations to the innerelectrode. A further firing is then done to complete the formation ofthe termination. For precious metal electrodes this firing is typicallydone in air at temperatures of about 500° C. to 900° C. For base metalsthis firing is typically done in nitrogen atmosphere at a temperature ofabout 600° C. to 1000° C. for about 0.1 to 1 hour.

Layers of nickel and tin may then be plated on the outer electrodes toenhance solderability and prevent oxidation of the outer electrodes.

A particularly preferred embodiment of the invention is illustrated inFIGS. 10A-10F wherein each electrode has a bulk region, 120, and asecondary region, 121, as illustrated in FIGS. 4A-F and describedrelative thereto. In FIGS. 10A-10F a tertiary region, 121′, is providedwhich is preferably identical to the secondary zone in shape and size.The secondary zone and tertiary zone can be different in shape and sizebut this is highly undesirable due to increases in manufacturingcomplexity as will be better understood from the discussion whichfollows.

The advantage of a symmetrical electrode, as described relative to FIGS.10A-10F will be discussed with reference to FIG. 11. In FIG. 11 aconductive region is illustrated, for convenience, having a rectangularbulk region and symmetrically disposed trapezoid secondary and tertiaryregions. A sheet, 700, is prepared with a multiplicity of identicalprint zones, 701, thereon. It is preferred that each print zone isseparated a distance, S, from the adjacent print zone as measuredbetween the narrowed ends. In practice, the distance S needs to besufficiently large to avoid any shorting or arching between subsequentprint regions. A separation of at least 0.20 mm (0.008 inches) issatisfactory. An advantage of this design is that the top and bottomshield electrodes and electrodes with both polarities can be made from acommon print. This eliminates the necessity for multiple print patternsand greatly improves manufacturability. By way of example, the sheet canbe cut along line, 702 and 702′, wherein each half of the illustratedprint zone will function as a shield electrode in the finished productas will be more clearly realized with reference to FIGS. 12-14 anddiscussion thereof. Similarly, the sheet can be cut along line, 703 and703′, which is intended to just separate the print zone, to form anactive layer of a first polarity by being attached to an externaltermination at the cut line. Similarly, the sheet can be cut along line,704 and 704′, to form an active layer of a second polarity. Cut line 702and 702′ are preferably centered within the print zone whereas cut lines703, 703′; 704 and 704′ are preferably just inside of the print zonethereby insuring adequate contact with the eventual externaltermination. The layers are cut along lines 705 and 705′ to isolateindividual capacitive units.

A capacitor formed utilizing the symmetrical electrode of FIG. 11 isillustrated in cross-sectional side view in FIG. 12. FIG. 13 is across-sectional view of the capacitor of FIG. 12 taken along line 13-13and FIG. 14 is a cross-sectional view of the capacitor of FIG. 12 takenalong line 14-14. In FIGS. 12-14, the active electrodes, 1111 and 1112,are of opposing polarity with alternate active electrodes in electricalcontact with opposing external terminations, 1113 and 1114. Tabs, 1019,are remnants of the cut pattern as realized from the cut patternsillustrated in FIG. 15. The tabs are not particularly preferred but arean artifact of the cutting operation. The shield electrodes, 1011, 1012,1013 and 1014, are disposed on each face, parallel to the activeelectrodes. Shield electrodes 1012 and 1013 are functional shields whichprotect the adjacent active electrode from arcing to the externaltermination in closest proximity. Shield electrodes, 1011 and 1014, areoptional electrodes provided for manufacturing convenience as understoodin the art. The optional insulating layer, 1116, is as discussed above.The shield electrodes are separated by a distance, S, which correspondsto the separation of the print zones as described relative to FIG. 11.

As would be realized from the discussion relative to FIGS. 11-14 thesymmetrical electrode pattern allows for a single pattern to be used forshield electrodes, and both actives, by merely shifting adjacent sheetsin a parallel arrangement. This greatly simplifies sheet placementduring capacitor manufacture and any sheet can function for any layerwithin the capacitor thereby minimizing the number of different partswhich must be manufactured.

EXAMPLES

The following examples use tapes made of the same material and with thesame fired thickness of 0.001″ (25.4 μm). All of the parts utilized a1206 case size manufactured with the same materials by the same processthe only factor affecting the electrical properties is the overlap areaA which is a function of the design of the internal conductiveelectrode. No coatings were applied to these capacitors. Conductordesigns are described in more detail in Table 1 and in the examples.

TABLE 1 Top & Total Number of Active or Intermediate Bottom ShieldExample Electrode Prints Active Electrode Prints Electrode Prints 1 4040 0 2 42 40 2 3 42 40 2 4 42 40 2 5 42 40 2 6 42 40 2 7 42 40 2 8 42 402

Comparative Example 1

A basic MLCC was manufactured using the active overlap pattern shown inFIG. 5 wherein for adjacent sheets the areas in the window overlap aswould be realized by one of skill in the art.

Comparative Example 2

A similar active design was used to the design described in Example 1above accept that additional first and last prints were added with a topand bottom shield electrode pattern with the intermediate activesidentical to those described in Example 1. This top and bottom shieldelectrode pattern is shown in FIG. 6 by overlaying the part area in thewindow with a window of the printed tape of FIG. 5.

Comparative Example 3

In addition to using the top and bottom shields described in Example 2the side shields were used in the intermediate actives as shown in FIG.7 below. Furthermore, in order to maximize the available overlap area,and so achieve the highest possible capacitance, only 2 side shields areemployed. It can also be seen that since the side shields are connectedto the opposite terminal of the capacitor breakdown caused by a lowinsulation pathway between a side shield and active would result in ashort circuit and catastrophic failure.

Inventive Examples 4-7

Top and bottom shields as described in Examples 2 and 3 were used butthere are no side shields in the active layers as described FIG. 7above. The inventive internal conductors eliminate the requirement forside shields by using secondary zones of the electrode to increase thedistance from the termination of opposite polarity and the end of theconductive inner layer. Although the tapering decreases the availableoverlap area compared to Examples 1 and 2 it still achieves a higherelectrical breakdown than either of these examples whilst retaining ahigher capacitance in all cases compared to Example 3. The dimensions,after firing, used in the inventive electrode designs of Examples 4, 5,6 and 7 are summarized in Table 2 with reference to FIG. 8. In this waycapacitance can be maximized whilst retaining a high voltage breakdownas noted in the electrical properties shown in Table 3.

TABLE 2 Example A⁴ (mm) A⁴ (inches) D⁴ (mm) D⁴ (inches) 4 0.998 0.03930.500 0.0197 5 2.02 0.0795 0.500 0.0197 6 0.998 0.0393 0.813 0.0320 72.02 0.0795 0.813 0.0320

Inventive Example 8

A semi-circle tapered design was used at the end of the electrode. Inthis case the maximum extent of the electrode (A⁴) is 2.02 mm (0.0795inches), after firing, which is the same as examples 5 and 7. Theintermediate active prints are shown in FIG. 9.

The electrical properties of Examples 1-8 are summarized in Table 3.

TABLE 3 Capacitance and Voltage Breakdown Dissipation Factor - 50 pcs inAir - 50 pcs (VDC) 48 hr Cap Cap Std Dev Cap % Std 48 hr Df Df Std DevStd. Example Mean (nF) (nF) Dev Mean (%) (%) Avg. Max. Min. Dev. 1137.48 0.86 0.63% 1.42 0.039 972 1350 730 146 2 141.00 1.44 1.02% 1.480.024 1347 1720 1060 156 3 81.01 0.74 0.91% 1.47 0.015 1712 2140 1120224 4 85.34 0.55 0.64% 1.49 0.010 1504 2070 1150 203 5 98.21 0.86 0.88%1.35 0.029 1653 1860 1270 118 6 98.09 1.44 1.47% 1.41 0.028 1635 18601210 166 7 109.06 0.74 0.68% 1.44 0.022 1635 1840 1350 138 8 107.37 0.630.58% 1.46 0.027 1603 1830 1150 188

This electrical data shows the average capacitance of an MLCC made withthe design described in Examples 4, 5, 6, 7 and 8 are higher than incomparative Example 3. Example 4 has a capacitance of 85.34 nF comparedto 81.01 nF for the patented design in Example 3. Example 4 has 5.3%more capacitance than Example 3. Table 3 shows the standard deviations(σ) associated with these capacitance measurements. The 3σ associatedwith Examples 3 and 4 are 2.22 nF and 1.65 nF, respectively, and sincethe increased capacitance of 4.33 nF is higher than the combination ofthese (3.87 nF) the results are significant. The minimum voltagebreakdown for Examples 4, 5, 6, and 7 are higher, in all cases, than theminimum of 1120 V recorded for Example 3. The minimum voltage breakdownis a good indicator of the design capability so the new designsdisclosed in Examples 4, 5, 6, 7 and 8 offers an increased capacitanceover Example 3 with similar voltage capability. The present inventionprovides capacitors with a break down voltage of over 1120 volts.

It should also be noted that although Examples 1 and 2 have the highestcapacitance their voltage breakdowns are lower than all the otherexamples. Furthermore, it can be seen that the highest minimum breakdownvoltage was 1350 V for Example 7, the highest capacitance obtained forthe inventive design that is 34.6% higher capacitance than Example 3.The semi-circle electrode pattern described in Example 8 has a similarcapacitance to Example 7 but the Average, Maximum and Minimun UVBD areall slightly less for Example 8.

Inventive Examples 9-12

Four batches of MLCC were manufactured with the electrode pattern ofFIG. 15 used for each layer. In FIG. 15, the top and bottom shieldlayers were ultimately formed by cutting the pattern shown in cut box1501. A first polarity active terminal, and related tab, were ultimatelyformed by cutting the pattern shown in cut box 1502 and a secondpolarity active terminal, and related tab, were ultimately formed bycutting the pattern shown in cut box 1503. The fired thickness of eachlayer was 25.4 μm (0.001 inch). Each MLCC was formed using 44 layers.The electrical properties of each batch are provided in Table 4.

TABLE 4 Capacitance and Dissipation Factor - 50pcs Cap 48 hr Std Cap %Df Voltage Breakdown 48 hr Cap Dev Std Mean Df Std in Air - 50 pcExample Mean (nF) (nF) Dev (%) Dev (%) Avg. Max. Min. Std. Dev. 9 95.571.58 1.65% 1.24 0.013 1781 2140 1330 256 10 95.71 1.04 1.09% 1.24 0.0121846 2170 1420 202 11 94.13 0.99 1.06% 1.10 0.013 1810 1930 1590 100 1294.85 0.87 0.92% 1.10 0.014 1837 2050 1690 103

As can be realized from the data presented in Table 4, a singleelectrode pattern provides a high capacitance with a high breakdownvoltage which is otherwise unavailable. The capacitance values exceedthose presented in Example 3 of U.S. Pat. No. 7,336,475 even allowingfor the additional capacitance attributable to and additional 2electrode prints which are used as shields. A single pattern would notbe useable in the teachings of U.S. Pat. No. 7,336,475 due to theformation of gaps in the top and bottom shields.

High voltage capacitor designs are demonstrated herein that providehigher capacitance and increased voltage handling capability thancurrently available in the prior art.

The invention has been described with particular reference to preferredembodiments without limitation thereto. One of skill in the art willrealize additional alterations, embodiments and examples which are notspecifically set forth but which are within the meets and bounds of theinvention as more specifically set forth in the claims appended hereto.

1. A capacitor comprising: first internal conductors and second internal conductors in an alternating layer wherein said first internal conductor has a first polarity and said second internal conductor has opposing polarity; a first external termination in electrical contact with said first internal conductors wherein said first external termination has a first side extension which extends a distance along a side of said capacitor which is perpendicular to said first internal conductors and said second internal conductors; a second external termination in electrical contact with said second internal conductors wherein said second external termination has a second side extension which extends a second distance along a second side of said capacitor which is perpendicular to said first internal conductors and said second internal conductors; wherein said first internal conductors extend towards said second external termination to a separation distance from said second external termination which is less than said second distance; wherein said first internal conductors comprise a bulk region and a secondary region wherein said secondary region has a region width which is less than a bulk width of said bulk region.
 2. The capacitor of claim 1 further comprising at least one shield layer parallel to said first internal conductors and of opposing polarity to a said first internal conductor and between said first internal conductor and an external termination of opposing polarity which is closest to said first internal conductor.
 3. The capacitor of claim 2 further comprising a multiplicity of shield layers parallel to said first internal conductors and at least two said shield layers are of opposing polarity to a closest internal conductor.
 4. The capacitor of claim 1 wherein said secondary region comprises at least one shape selected from the group consisting of semi-round, trapezoidal, rectangular, partially rounded rectangular, and concave trapezoid.
 5. The capacitor of claim 4 wherein said secondary region comprises at least one shape selected from the group consisting of semicircle, semi-oval and semi-obround.
 6. The capacitor of claim 4 wherein said rectangular has a length which is perpendicular to, and shorter than, a width of said bulk zone.
 7. The capacitor of claim 1 wherein said bulk zone has a height, which is at least 66% of the length of said first internal conductor as measured from said first external termination.
 8. The capacitor of claim 1 with voltage breakdown of greater than 1120 V.
 9. The capacitor of claim 8 with voltage breakdown of greater than 1500 V.
 10. A capacitor comprising: first internal conductors and second internal conductors in an alternating layer wherein said first internal conductor has a first polarity and said second internal conductor has opposing polarity; a first external termination in electrical contact with said first internal conductors wherein said first external termination has a first side extension which extends a distance along a side of said capacitor which is perpendicular to said first internal conductors and said second internal conductors; a second external termination in electrical contact with said second internal conductors wherein said second external termination has a second side extension which extends a second distance along a second side of said capacitor which is perpendicular to said first internal conductors and said second internal conductors; wherein said first internal conductors extend towards said second external termination to a separation distance from said second external termination which is less than said second distance; wherein said first internal conductors comprise a bulk region and a secondary region wherein said secondary region is further from said second side extension than said second distance.
 11. The capacitor of claim 10 further comprising at least one shield layer parallel to said first internal conductors and said second internal conductors and of opposing polarity to a closest internal conductor and between said closest internal conductor and an external termination of opposing polarity which is closest to said closest internal conductor.
 12. The capacitor of claim 11 further comprising a multiplicity of shield layers parallel to said first internal conductors and said second internal conductors and at least two said shield layers are of opposing polarity to a closest internal conductor.
 13. The capacitor of claim 10 wherein said secondary region comprises at least one shape selected from the group consisting of semi-round, trapezoidal, rectangular, partially rounded rectangular, and concave trapezoid.
 14. The capacitor of claim 13 wherein said secondary region comprises at least one shape selected from the group consisting of semicircle, semi-oval and semi-obround.
 15. The capacitor of claim 13 wherein said rectangular has a length which is perpendicular to, and shorter than, a width of said bulk zone.
 16. The capacitor of claim 10 wherein said bulk zone has a height, which is at least 66% of the length of said first internal conductor as measured from said first external termination.
 17. The capacitor of claim 10 with voltage breakdown of greater than 1120 V.
 18. The capacitor of claim 17 with voltage breakdown of greater than 1500 V.
 19. A method of forming a multilayered ceramic capacitor comprising: printing a pattern of print regions of conductive material on a series of sheets wherein each print region of said print regions comprises a bulk region and a secondary region wherein said secondary region has a region width which is less than a bulk width of said bulk region; forming a layered assembly by the steps of: overlaying a first sheet over a bottom sheet in parallel offset fashion wherein at least one said print region of said bottom sheet is overlapped but laterally offset from a print region of said first sheet with a dielectric precursor between said overlapped but laterally offset print regions; overlaying a second sheet over said first sheet wherein at least one said print region of said second sheet is overlapped but offset from said print region of said first sheet and said print region of said bottom sheet with a dielectric between said overlapped but laterally offset print regions; overlaying additional sheets with alternating sheets having said print region aligned with said first sheet and said second sheet respectively with a dielectric between said overlapped but laterally offset print regions, overlaying a top sheet with said print region aligned with said bottom sheet with a dielectric between said overlapped but laterally offset print regions; dicing said un-fired, compacted sheets to isolate a layered structure with print regions of said first layer forming first internal conductors; print regions of said second layer forming second internal conductors and print regions of said top sheet and said bottom sheet forming shield layers; firing said layered assembly to remove organic materials and fuse said sheets to form a fired monolith; forming a first external termination in electrical contact with said first internal conductors on said fired monolith; and forming a second external termination in electrical contact with said second internal conductors on said fired monolith.
 20. The method of forming a multilayered ceramic capacitor of claim 19 wherein said secondary region comprises at least one shape selected from the group consisting of semi-round, trapezoidal, rectangular, partially rounded rectangular, and concave trapezoid.
 21. The method of forming a multilayered ceramic capacitor of claim 20 wherein said secondary region comprises at least one shape selected from the group consisting of semicircle, semi-oval and semi-obround.
 22. The method of forming a multilayered ceramic capacitor of claim 20 wherein said rectangular has a length which is perpendicular to, and shorter than, a width of said bulk zone.
 23. The method of forming a multilayered ceramic capacitor of claim 19 wherein said bulk zone has a height, which is at least 66% of the length of said first internal conductor as measured from said first external termination.
 24. The method of forming a multilayered ceramic capacitor of claim 19 with voltage breakdown of greater than 1120 V.
 25. The method of forming a multilayered ceramic capacitor of claim 24 with voltage breakdown of greater than 1500 V.
 26. The method of forming a multilayered ceramic capacitor of claim 19 wherein each said print region further comprises a tertiary region opposite said secondary region.
 27. The method of forming a multilayered ceramic capacitor of claim 26 wherein each said print region is symmetrical.
 28. The method of forming a multilayered ceramic capacitor of claim 26 wherein said tertiary region comprises at least one shape selected from the group consisting of semi-round, trapezoidal, rectangular, partially rounded rectangular, and concave trapezoid.
 29. The method of forming a multilayered ceramic capacitor of claim 28 wherein said tertiary region comprises at least one shape selected from the group consisting of semicircle, semi-oval and semi-obround.
 30. The method of forming a multilayered ceramic capacitor of claim 28 wherein said rectangular has a length which is perpendicular to, and shorter than, a width of said bulk zone. 